1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 #endif /* not lint */ 35 #include <sys/cdefs.h> 36 #include <paths.h> 37 #include <signal.h> 38 #include <stdlib.h> 39 #include <unistd.h> 40 #include <sys/resource.h> 41 #include <errno.h> 42 43 /* 44 * Evaluate a command. 45 */ 46 47 #include "shell.h" 48 #include "nodes.h" 49 #include "syntax.h" 50 #include "expand.h" 51 #include "parser.h" 52 #include "jobs.h" 53 #include "eval.h" 54 #include "builtins.h" 55 #include "options.h" 56 #include "exec.h" 57 #include "redir.h" 58 #include "input.h" 59 #include "output.h" 60 #include "trap.h" 61 #include "var.h" 62 #include "memalloc.h" 63 #include "error.h" 64 #include "show.h" 65 #include "mystring.h" 66 #ifndef NO_HISTORY 67 #include "myhistedit.h" 68 #endif 69 70 71 int evalskip; /* set if we are skipping commands */ 72 int skipcount; /* number of levels to skip */ 73 static int loopnest; /* current loop nesting level */ 74 int funcnest; /* depth of function calls */ 75 static int builtin_flags; /* evalcommand flags for builtins */ 76 77 78 char *commandname; 79 struct arglist *cmdenviron; 80 int exitstatus; /* exit status of last command */ 81 int oexitstatus; /* saved exit status */ 82 83 84 static void evalloop(union node *, int); 85 static void evalfor(union node *, int); 86 static union node *evalcase(union node *); 87 static void evalsubshell(union node *, int); 88 static void evalredir(union node *, int); 89 static void exphere(union node *, struct arglist *); 90 static void expredir(union node *); 91 static void evalpipe(union node *); 92 static int is_valid_fast_cmdsubst(union node *n); 93 static void evalcommand(union node *, int, struct backcmd *); 94 static void prehash(union node *); 95 96 97 /* 98 * Called to reset things after an exception. 99 */ 100 101 void 102 reseteval(void) 103 { 104 evalskip = 0; 105 loopnest = 0; 106 } 107 108 109 /* 110 * The eval command. 111 */ 112 113 int 114 evalcmd(int argc, char **argv) 115 { 116 char *p; 117 char *concat; 118 char **ap; 119 120 if (argc > 1) { 121 p = argv[1]; 122 if (argc > 2) { 123 STARTSTACKSTR(concat); 124 ap = argv + 2; 125 for (;;) { 126 STPUTS(p, concat); 127 if ((p = *ap++) == NULL) 128 break; 129 STPUTC(' ', concat); 130 } 131 STPUTC('\0', concat); 132 p = grabstackstr(concat); 133 } 134 evalstring(p, builtin_flags); 135 } else 136 exitstatus = 0; 137 return exitstatus; 138 } 139 140 141 /* 142 * Execute a command or commands contained in a string. 143 */ 144 145 void 146 evalstring(const char *s, int flags) 147 { 148 union node *n; 149 struct stackmark smark; 150 int flags_exit; 151 int any; 152 153 flags_exit = flags & EV_EXIT; 154 flags &= ~EV_EXIT; 155 any = 0; 156 setstackmark(&smark); 157 setinputstring(s, 1); 158 while ((n = parsecmd(0)) != NEOF) { 159 if (n != NULL && !nflag) { 160 if (flags_exit && preadateof()) 161 evaltree(n, flags | EV_EXIT); 162 else 163 evaltree(n, flags); 164 any = 1; 165 if (evalskip) 166 break; 167 } 168 popstackmark(&smark); 169 setstackmark(&smark); 170 } 171 popfile(); 172 popstackmark(&smark); 173 if (!any) 174 exitstatus = 0; 175 if (flags_exit) 176 exraise(EXEXIT); 177 } 178 179 180 /* 181 * Evaluate a parse tree. The value is left in the global variable 182 * exitstatus. 183 */ 184 185 void 186 evaltree(union node *n, int flags) 187 { 188 int do_etest; 189 union node *next; 190 struct stackmark smark; 191 192 setstackmark(&smark); 193 do_etest = 0; 194 if (n == NULL) { 195 TRACE(("evaltree(NULL) called\n")); 196 exitstatus = 0; 197 goto out; 198 } 199 do { 200 next = NULL; 201 #ifndef NO_HISTORY 202 displayhist = 1; /* show history substitutions done with fc */ 203 #endif 204 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 205 switch (n->type) { 206 case NSEMI: 207 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 208 if (evalskip) 209 goto out; 210 next = n->nbinary.ch2; 211 break; 212 case NAND: 213 evaltree(n->nbinary.ch1, EV_TESTED); 214 if (evalskip || exitstatus != 0) { 215 goto out; 216 } 217 next = n->nbinary.ch2; 218 break; 219 case NOR: 220 evaltree(n->nbinary.ch1, EV_TESTED); 221 if (evalskip || exitstatus == 0) 222 goto out; 223 next = n->nbinary.ch2; 224 break; 225 case NREDIR: 226 evalredir(n, flags); 227 break; 228 case NSUBSHELL: 229 evalsubshell(n, flags); 230 do_etest = !(flags & EV_TESTED); 231 break; 232 case NBACKGND: 233 evalsubshell(n, flags); 234 break; 235 case NIF: { 236 evaltree(n->nif.test, EV_TESTED); 237 if (evalskip) 238 goto out; 239 if (exitstatus == 0) 240 next = n->nif.ifpart; 241 else if (n->nif.elsepart) 242 next = n->nif.elsepart; 243 else 244 exitstatus = 0; 245 break; 246 } 247 case NWHILE: 248 case NUNTIL: 249 evalloop(n, flags & ~EV_EXIT); 250 break; 251 case NFOR: 252 evalfor(n, flags & ~EV_EXIT); 253 break; 254 case NCASE: 255 next = evalcase(n); 256 break; 257 case NCLIST: 258 next = n->nclist.body; 259 break; 260 case NCLISTFALLTHRU: 261 if (n->nclist.body) { 262 evaltree(n->nclist.body, flags & ~EV_EXIT); 263 if (evalskip) 264 goto out; 265 } 266 next = n->nclist.next; 267 break; 268 case NDEFUN: 269 defun(n->narg.text, n->narg.next); 270 exitstatus = 0; 271 break; 272 case NNOT: 273 evaltree(n->nnot.com, EV_TESTED); 274 if (evalskip) 275 goto out; 276 exitstatus = !exitstatus; 277 break; 278 279 case NPIPE: 280 evalpipe(n); 281 do_etest = !(flags & EV_TESTED); 282 break; 283 case NCMD: 284 evalcommand(n, flags, (struct backcmd *)NULL); 285 do_etest = !(flags & EV_TESTED); 286 break; 287 default: 288 out1fmt("Node type = %d\n", n->type); 289 flushout(&output); 290 break; 291 } 292 n = next; 293 popstackmark(&smark); 294 setstackmark(&smark); 295 } while (n != NULL); 296 out: 297 popstackmark(&smark); 298 if (pendingsig) 299 dotrap(); 300 if (eflag && exitstatus != 0 && do_etest) 301 exitshell(exitstatus); 302 if (flags & EV_EXIT) 303 exraise(EXEXIT); 304 } 305 306 307 static void 308 evalloop(union node *n, int flags) 309 { 310 int status; 311 312 loopnest++; 313 status = 0; 314 for (;;) { 315 if (!evalskip) 316 evaltree(n->nbinary.ch1, EV_TESTED); 317 if (evalskip) { 318 if (evalskip == SKIPCONT && --skipcount <= 0) { 319 evalskip = 0; 320 continue; 321 } 322 if (evalskip == SKIPBREAK && --skipcount <= 0) 323 evalskip = 0; 324 if (evalskip == SKIPRETURN) 325 status = exitstatus; 326 break; 327 } 328 if (n->type == NWHILE) { 329 if (exitstatus != 0) 330 break; 331 } else { 332 if (exitstatus == 0) 333 break; 334 } 335 evaltree(n->nbinary.ch2, flags); 336 status = exitstatus; 337 } 338 loopnest--; 339 exitstatus = status; 340 } 341 342 343 344 static void 345 evalfor(union node *n, int flags) 346 { 347 struct arglist arglist; 348 union node *argp; 349 int i; 350 int status; 351 352 emptyarglist(&arglist); 353 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 354 oexitstatus = exitstatus; 355 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 356 } 357 358 loopnest++; 359 status = 0; 360 for (i = 0; i < arglist.count; i++) { 361 setvar(n->nfor.var, arglist.args[i], 0); 362 evaltree(n->nfor.body, flags); 363 status = exitstatus; 364 if (evalskip) { 365 if (evalskip == SKIPCONT && --skipcount <= 0) { 366 evalskip = 0; 367 continue; 368 } 369 if (evalskip == SKIPBREAK && --skipcount <= 0) 370 evalskip = 0; 371 break; 372 } 373 } 374 loopnest--; 375 exitstatus = status; 376 } 377 378 379 /* 380 * Evaluate a case statement, returning the selected tree. 381 * 382 * The exit status needs care to get right. 383 */ 384 385 static union node * 386 evalcase(union node *n) 387 { 388 union node *cp; 389 union node *patp; 390 struct arglist arglist; 391 392 emptyarglist(&arglist); 393 oexitstatus = exitstatus; 394 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 395 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 396 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 397 if (casematch(patp, arglist.args[0])) { 398 while (cp->nclist.next && 399 cp->type == NCLISTFALLTHRU && 400 cp->nclist.body == NULL) 401 cp = cp->nclist.next; 402 if (cp->nclist.next && 403 cp->type == NCLISTFALLTHRU) 404 return (cp); 405 if (cp->nclist.body == NULL) 406 exitstatus = 0; 407 return (cp->nclist.body); 408 } 409 } 410 } 411 exitstatus = 0; 412 return (NULL); 413 } 414 415 416 417 /* 418 * Kick off a subshell to evaluate a tree. 419 */ 420 421 static void 422 evalsubshell(union node *n, int flags) 423 { 424 struct job *jp; 425 int backgnd = (n->type == NBACKGND); 426 427 oexitstatus = exitstatus; 428 expredir(n->nredir.redirect); 429 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 430 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 431 if (backgnd) 432 flags &=~ EV_TESTED; 433 redirect(n->nredir.redirect, 0); 434 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 435 } else if (! backgnd) { 436 INTOFF; 437 exitstatus = waitforjob(jp, (int *)NULL); 438 INTON; 439 } else 440 exitstatus = 0; 441 } 442 443 444 /* 445 * Evaluate a redirected compound command. 446 */ 447 448 static void 449 evalredir(union node *n, int flags) 450 { 451 struct jmploc jmploc; 452 struct jmploc *savehandler; 453 volatile int in_redirect = 1; 454 455 oexitstatus = exitstatus; 456 expredir(n->nredir.redirect); 457 savehandler = handler; 458 if (setjmp(jmploc.loc)) { 459 int e; 460 461 handler = savehandler; 462 e = exception; 463 popredir(); 464 if (e == EXERROR && in_redirect) { 465 FORCEINTON; 466 return; 467 } 468 longjmp(handler->loc, 1); 469 } else { 470 INTOFF; 471 handler = &jmploc; 472 redirect(n->nredir.redirect, REDIR_PUSH); 473 in_redirect = 0; 474 INTON; 475 evaltree(n->nredir.n, flags); 476 } 477 INTOFF; 478 handler = savehandler; 479 popredir(); 480 INTON; 481 } 482 483 484 static void 485 exphere(union node *redir, struct arglist *fn) 486 { 487 struct jmploc jmploc; 488 struct jmploc *savehandler; 489 struct localvar *savelocalvars; 490 int need_longjmp = 0; 491 unsigned char saveoptreset; 492 493 redir->nhere.expdoc = ""; 494 savelocalvars = localvars; 495 localvars = NULL; 496 saveoptreset = shellparam.reset; 497 forcelocal++; 498 savehandler = handler; 499 if (setjmp(jmploc.loc)) 500 need_longjmp = exception != EXERROR; 501 else { 502 handler = &jmploc; 503 expandarg(redir->nhere.doc, fn, 0); 504 redir->nhere.expdoc = fn->args[0]; 505 INTOFF; 506 } 507 handler = savehandler; 508 forcelocal--; 509 poplocalvars(); 510 localvars = savelocalvars; 511 shellparam.reset = saveoptreset; 512 if (need_longjmp) 513 longjmp(handler->loc, 1); 514 INTON; 515 } 516 517 518 /* 519 * Compute the names of the files in a redirection list. 520 */ 521 522 static void 523 expredir(union node *n) 524 { 525 union node *redir; 526 527 for (redir = n ; redir ; redir = redir->nfile.next) { 528 struct arglist fn; 529 emptyarglist(&fn); 530 switch (redir->type) { 531 case NFROM: 532 case NTO: 533 case NFROMTO: 534 case NAPPEND: 535 case NCLOBBER: 536 expandarg(redir->nfile.fname, &fn, EXP_TILDE); 537 redir->nfile.expfname = fn.args[0]; 538 break; 539 case NFROMFD: 540 case NTOFD: 541 if (redir->ndup.vname) { 542 expandarg(redir->ndup.vname, &fn, EXP_TILDE); 543 fixredir(redir, fn.args[0], 1); 544 } 545 break; 546 case NXHERE: 547 exphere(redir, &fn); 548 break; 549 } 550 } 551 } 552 553 554 555 /* 556 * Evaluate a pipeline. All the processes in the pipeline are children 557 * of the process creating the pipeline. (This differs from some versions 558 * of the shell, which make the last process in a pipeline the parent 559 * of all the rest.) 560 */ 561 562 static void 563 evalpipe(union node *n) 564 { 565 struct job *jp; 566 struct nodelist *lp; 567 int pipelen; 568 int prevfd; 569 int pip[2]; 570 571 TRACE(("evalpipe(%p) called\n", (void *)n)); 572 pipelen = 0; 573 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 574 pipelen++; 575 INTOFF; 576 jp = makejob(n, pipelen); 577 prevfd = -1; 578 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 579 prehash(lp->n); 580 pip[1] = -1; 581 if (lp->next) { 582 if (pipe(pip) < 0) { 583 if (prevfd >= 0) 584 close(prevfd); 585 error("Pipe call failed: %s", strerror(errno)); 586 } 587 } 588 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 589 INTON; 590 if (prevfd > 0) { 591 dup2(prevfd, 0); 592 close(prevfd); 593 } 594 if (pip[1] >= 0) { 595 if (!(prevfd >= 0 && pip[0] == 0)) 596 close(pip[0]); 597 if (pip[1] != 1) { 598 dup2(pip[1], 1); 599 close(pip[1]); 600 } 601 } 602 evaltree(lp->n, EV_EXIT); 603 } 604 if (prevfd >= 0) 605 close(prevfd); 606 prevfd = pip[0]; 607 if (pip[1] != -1) 608 close(pip[1]); 609 } 610 INTON; 611 if (n->npipe.backgnd == 0) { 612 INTOFF; 613 exitstatus = waitforjob(jp, (int *)NULL); 614 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 615 INTON; 616 } else 617 exitstatus = 0; 618 } 619 620 621 622 static int 623 is_valid_fast_cmdsubst(union node *n) 624 { 625 626 return (n->type == NCMD); 627 } 628 629 /* 630 * Execute a command inside back quotes. If it's a builtin command, we 631 * want to save its output in a block obtained from malloc. Otherwise 632 * we fork off a subprocess and get the output of the command via a pipe. 633 * Should be called with interrupts off. 634 */ 635 636 void 637 evalbackcmd(union node *n, struct backcmd *result) 638 { 639 int pip[2]; 640 struct job *jp; 641 struct stackmark smark; 642 struct jmploc jmploc; 643 struct jmploc *savehandler; 644 struct localvar *savelocalvars; 645 unsigned char saveoptreset; 646 647 result->fd = -1; 648 result->buf = NULL; 649 result->nleft = 0; 650 result->jp = NULL; 651 if (n == NULL) { 652 exitstatus = 0; 653 return; 654 } 655 setstackmark(&smark); 656 exitstatus = oexitstatus; 657 if (is_valid_fast_cmdsubst(n)) { 658 savelocalvars = localvars; 659 localvars = NULL; 660 saveoptreset = shellparam.reset; 661 forcelocal++; 662 savehandler = handler; 663 if (setjmp(jmploc.loc)) { 664 if (exception == EXERROR) 665 /* nothing */; 666 else if (exception != 0) { 667 handler = savehandler; 668 forcelocal--; 669 poplocalvars(); 670 localvars = savelocalvars; 671 shellparam.reset = saveoptreset; 672 longjmp(handler->loc, 1); 673 } 674 } else { 675 handler = &jmploc; 676 evalcommand(n, EV_BACKCMD, result); 677 } 678 handler = savehandler; 679 forcelocal--; 680 poplocalvars(); 681 localvars = savelocalvars; 682 shellparam.reset = saveoptreset; 683 } else { 684 if (pipe(pip) < 0) 685 error("Pipe call failed: %s", strerror(errno)); 686 jp = makejob(n, 1); 687 if (forkshell(jp, n, FORK_NOJOB) == 0) { 688 FORCEINTON; 689 close(pip[0]); 690 if (pip[1] != 1) { 691 dup2(pip[1], 1); 692 close(pip[1]); 693 } 694 evaltree(n, EV_EXIT); 695 } 696 close(pip[1]); 697 result->fd = pip[0]; 698 result->jp = jp; 699 } 700 popstackmark(&smark); 701 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 702 result->fd, result->buf, result->nleft, result->jp)); 703 } 704 705 static int 706 mustexpandto(const char *argtext, const char *mask) 707 { 708 for (;;) { 709 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 710 argtext++; 711 continue; 712 } 713 if (*argtext == CTLESC) 714 argtext++; 715 else if (BASESYNTAX[(int)*argtext] == CCTL) 716 return (0); 717 if (*argtext != *mask) 718 return (0); 719 if (*argtext == '\0') 720 return (1); 721 argtext++; 722 mask++; 723 } 724 } 725 726 static int 727 isdeclarationcmd(struct narg *arg) 728 { 729 int have_command = 0; 730 731 if (arg == NULL) 732 return (0); 733 while (mustexpandto(arg->text, "command")) { 734 have_command = 1; 735 arg = &arg->next->narg; 736 if (arg == NULL) 737 return (0); 738 /* 739 * To also allow "command -p" and "command --" as part of 740 * a declaration command, add code here. 741 * We do not do this, as ksh does not do it either and it 742 * is not required by POSIX. 743 */ 744 } 745 return (mustexpandto(arg->text, "export") || 746 mustexpandto(arg->text, "readonly") || 747 (mustexpandto(arg->text, "local") && 748 (have_command || !isfunc("local")))); 749 } 750 751 static void 752 xtracecommand(struct arglist *varlist, int argc, char **argv) 753 { 754 char sep = 0; 755 const char *text, *p, *ps4; 756 int i; 757 758 ps4 = expandstr(ps4val()); 759 out2str(ps4 != NULL ? ps4 : ps4val()); 760 for (i = 0; i < varlist->count; i++) { 761 text = varlist->args[i]; 762 if (sep != 0) 763 out2c(' '); 764 p = strchr(text, '='); 765 if (p != NULL) { 766 p++; 767 outbin(text, p - text, out2); 768 out2qstr(p); 769 } else 770 out2qstr(text); 771 sep = ' '; 772 } 773 for (i = 0; i < argc; i++) { 774 text = argv[i]; 775 if (sep != 0) 776 out2c(' '); 777 out2qstr(text); 778 sep = ' '; 779 } 780 out2c('\n'); 781 flushout(&errout); 782 } 783 784 /* 785 * Check if a builtin can safely be executed in the same process, 786 * even though it should be in a subshell (command substitution). 787 * Note that jobid, jobs, times and trap can show information not 788 * available in a child process; this is deliberate. 789 * The arguments should already have been expanded. 790 */ 791 static int 792 safe_builtin(int idx, int argc, char **argv) 793 { 794 /* Generated from builtins.def. */ 795 if (safe_builtin_always(idx)) 796 return (1); 797 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 798 idx == UMASKCMD) 799 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 800 if (idx == SETCMD) 801 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 802 argv[1][0] == '+') && argv[1][1] == 'o' && 803 argv[1][2] == '\0')); 804 return (0); 805 } 806 807 /* 808 * Execute a simple command. 809 * Note: This may or may not return if (flags & EV_EXIT). 810 */ 811 812 static void 813 evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 814 { 815 union node *argp; 816 struct arglist arglist; 817 struct arglist varlist; 818 char **argv; 819 int argc; 820 char **envp; 821 int varflag; 822 int mode; 823 int pip[2]; 824 struct cmdentry cmdentry; 825 struct job *jp; 826 struct jmploc jmploc; 827 struct jmploc *savehandler; 828 char *savecmdname; 829 struct shparam saveparam; 830 struct localvar *savelocalvars; 831 struct parsefile *savetopfile; 832 volatile int e; 833 char *lastarg; 834 int signaled; 835 int do_clearcmdentry; 836 const char *path = pathval(); 837 int i; 838 839 /* First expand the arguments. */ 840 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 841 emptyarglist(&arglist); 842 emptyarglist(&varlist); 843 varflag = 1; 844 jp = NULL; 845 do_clearcmdentry = 0; 846 oexitstatus = exitstatus; 847 exitstatus = 0; 848 /* Add one slot at the beginning for tryexec(). */ 849 appendarglist(&arglist, nullstr); 850 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 851 if (varflag && isassignment(argp->narg.text)) { 852 expandarg(argp, varflag == 1 ? &varlist : &arglist, 853 EXP_VARTILDE); 854 continue; 855 } else if (varflag == 1) 856 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 857 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 858 } 859 appendarglist(&arglist, nullstr); 860 expredir(cmd->ncmd.redirect); 861 argc = arglist.count - 2; 862 argv = &arglist.args[1]; 863 864 argv[argc] = NULL; 865 lastarg = NULL; 866 if (iflag && funcnest == 0 && argc > 0) 867 lastarg = argv[argc - 1]; 868 869 /* Print the command if xflag is set. */ 870 if (xflag) 871 xtracecommand(&varlist, argc, argv); 872 873 /* Now locate the command. */ 874 if (argc == 0) { 875 /* Variable assignment(s) without command */ 876 cmdentry.cmdtype = CMDBUILTIN; 877 cmdentry.u.index = BLTINCMD; 878 cmdentry.special = 0; 879 } else { 880 static const char PATH[] = "PATH="; 881 int cmd_flags = 0, bltinonly = 0; 882 883 /* 884 * Modify the command lookup path, if a PATH= assignment 885 * is present 886 */ 887 for (i = 0; i < varlist.count; i++) 888 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) { 889 path = varlist.args[i] + sizeof(PATH) - 1; 890 /* 891 * On `PATH=... command`, we need to make 892 * sure that the command isn't using the 893 * non-updated hash table of the outer PATH 894 * setting and we need to make sure that 895 * the hash table isn't filled with items 896 * from the temporary setting. 897 * 898 * It would be better to forbid using and 899 * updating the table while this command 900 * runs, by the command finding mechanism 901 * is heavily integrated with hash handling, 902 * so we just delete the hash before and after 903 * the command runs. Partly deleting like 904 * changepatch() does doesn't seem worth the 905 * bookinging effort, since most such runs add 906 * directories in front of the new PATH. 907 */ 908 clearcmdentry(); 909 do_clearcmdentry = 1; 910 } 911 912 for (;;) { 913 if (bltinonly) { 914 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 915 if (cmdentry.u.index < 0) { 916 cmdentry.u.index = BLTINCMD; 917 argv--; 918 argc++; 919 break; 920 } 921 } else 922 find_command(argv[0], &cmdentry, cmd_flags, path); 923 /* implement the bltin and command builtins here */ 924 if (cmdentry.cmdtype != CMDBUILTIN) 925 break; 926 if (cmdentry.u.index == BLTINCMD) { 927 if (argc == 1) 928 break; 929 argv++; 930 argc--; 931 bltinonly = 1; 932 } else if (cmdentry.u.index == COMMANDCMD) { 933 if (argc == 1) 934 break; 935 if (!strcmp(argv[1], "-p")) { 936 if (argc == 2) 937 break; 938 if (argv[2][0] == '-') { 939 if (strcmp(argv[2], "--")) 940 break; 941 if (argc == 3) 942 break; 943 argv += 3; 944 argc -= 3; 945 } else { 946 argv += 2; 947 argc -= 2; 948 } 949 path = _PATH_STDPATH; 950 clearcmdentry(); 951 do_clearcmdentry = 1; 952 } else if (!strcmp(argv[1], "--")) { 953 if (argc == 2) 954 break; 955 argv += 2; 956 argc -= 2; 957 } else if (argv[1][0] == '-') 958 break; 959 else { 960 argv++; 961 argc--; 962 } 963 cmd_flags |= DO_NOFUNC; 964 bltinonly = 0; 965 } else 966 break; 967 } 968 /* 969 * Special builtins lose their special properties when 970 * called via 'command'. 971 */ 972 if (cmd_flags & DO_NOFUNC) 973 cmdentry.special = 0; 974 } 975 976 /* Fork off a child process if necessary. */ 977 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 978 && ((flags & EV_EXIT) == 0 || have_traps())) 979 || ((flags & EV_BACKCMD) != 0 980 && (cmdentry.cmdtype != CMDBUILTIN || 981 !safe_builtin(cmdentry.u.index, argc, argv)))) { 982 jp = makejob(cmd, 1); 983 mode = FORK_FG; 984 if (flags & EV_BACKCMD) { 985 mode = FORK_NOJOB; 986 if (pipe(pip) < 0) 987 error("Pipe call failed: %s", strerror(errno)); 988 } 989 if (cmdentry.cmdtype == CMDNORMAL && 990 cmd->ncmd.redirect == NULL && 991 varlist.count == 0 && 992 (mode == FORK_FG || mode == FORK_NOJOB) && 993 !disvforkset() && !iflag && !mflag) { 994 vforkexecshell(jp, argv, environment(), path, 995 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL); 996 goto parent; 997 } 998 if (forkshell(jp, cmd, mode) != 0) 999 goto parent; /* at end of routine */ 1000 if (flags & EV_BACKCMD) { 1001 FORCEINTON; 1002 close(pip[0]); 1003 if (pip[1] != 1) { 1004 dup2(pip[1], 1); 1005 close(pip[1]); 1006 } 1007 flags &= ~EV_BACKCMD; 1008 } 1009 flags |= EV_EXIT; 1010 } 1011 1012 /* This is the child process if a fork occurred. */ 1013 /* Execute the command. */ 1014 if (cmdentry.cmdtype == CMDFUNCTION) { 1015 #ifdef DEBUG 1016 trputs("Shell function: "); trargs(argv); 1017 #endif 1018 saveparam = shellparam; 1019 shellparam.malloc = 0; 1020 shellparam.reset = 1; 1021 shellparam.nparam = argc - 1; 1022 shellparam.p = argv + 1; 1023 shellparam.optp = NULL; 1024 shellparam.optnext = NULL; 1025 INTOFF; 1026 savelocalvars = localvars; 1027 localvars = NULL; 1028 reffunc(cmdentry.u.func); 1029 savehandler = handler; 1030 if (setjmp(jmploc.loc)) { 1031 popredir(); 1032 unreffunc(cmdentry.u.func); 1033 poplocalvars(); 1034 localvars = savelocalvars; 1035 freeparam(&shellparam); 1036 shellparam = saveparam; 1037 funcnest--; 1038 handler = savehandler; 1039 longjmp(handler->loc, 1); 1040 } 1041 handler = &jmploc; 1042 funcnest++; 1043 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1044 INTON; 1045 for (i = 0; i < varlist.count; i++) 1046 mklocal(varlist.args[i]); 1047 exitstatus = oexitstatus; 1048 evaltree(getfuncnode(cmdentry.u.func), 1049 flags & (EV_TESTED | EV_EXIT)); 1050 INTOFF; 1051 unreffunc(cmdentry.u.func); 1052 poplocalvars(); 1053 localvars = savelocalvars; 1054 freeparam(&shellparam); 1055 shellparam = saveparam; 1056 handler = savehandler; 1057 funcnest--; 1058 popredir(); 1059 INTON; 1060 if (evalskip == SKIPRETURN) { 1061 evalskip = 0; 1062 skipcount = 0; 1063 } 1064 if (jp) 1065 exitshell(exitstatus); 1066 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1067 #ifdef DEBUG 1068 trputs("builtin command: "); trargs(argv); 1069 #endif 1070 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1071 if (flags == EV_BACKCMD) { 1072 memout.nextc = memout.buf; 1073 mode |= REDIR_BACKQ; 1074 } 1075 savecmdname = commandname; 1076 savetopfile = getcurrentfile(); 1077 cmdenviron = &varlist; 1078 e = -1; 1079 savehandler = handler; 1080 if (setjmp(jmploc.loc)) { 1081 e = exception; 1082 if (e == EXINT) 1083 exitstatus = SIGINT+128; 1084 goto cmddone; 1085 } 1086 handler = &jmploc; 1087 redirect(cmd->ncmd.redirect, mode); 1088 outclearerror(out1); 1089 /* 1090 * If there is no command word, redirection errors should 1091 * not be fatal but assignment errors should. 1092 */ 1093 if (argc == 0) 1094 cmdentry.special = 1; 1095 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1096 if (argc > 0) 1097 bltinsetlocale(); 1098 commandname = argv[0]; 1099 argptr = argv + 1; 1100 nextopt_optptr = NULL; /* initialize nextopt */ 1101 builtin_flags = flags; 1102 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1103 flushall(); 1104 if (outiserror(out1)) { 1105 warning("write error on stdout"); 1106 if (exitstatus == 0 || exitstatus == 1) 1107 exitstatus = 2; 1108 } 1109 cmddone: 1110 if (argc > 0) 1111 bltinunsetlocale(); 1112 cmdenviron = NULL; 1113 out1 = &output; 1114 out2 = &errout; 1115 freestdout(); 1116 handler = savehandler; 1117 commandname = savecmdname; 1118 if (jp) 1119 exitshell(exitstatus); 1120 if (flags == EV_BACKCMD) { 1121 backcmd->buf = memout.buf; 1122 backcmd->nleft = memout.buf != NULL ? 1123 memout.nextc - memout.buf : 0; 1124 memout.buf = NULL; 1125 memout.nextc = NULL; 1126 memout.bufend = NULL; 1127 memout.bufsize = 64; 1128 } 1129 if (cmdentry.u.index != EXECCMD) 1130 popredir(); 1131 if (e != -1) { 1132 if (e != EXERROR || cmdentry.special) 1133 exraise(e); 1134 popfilesupto(savetopfile); 1135 if (flags != EV_BACKCMD) 1136 FORCEINTON; 1137 } 1138 } else { 1139 #ifdef DEBUG 1140 trputs("normal command: "); trargs(argv); 1141 #endif 1142 redirect(cmd->ncmd.redirect, 0); 1143 for (i = 0; i < varlist.count; i++) 1144 setvareq(varlist.args[i], VEXPORT|VSTACK); 1145 envp = environment(); 1146 shellexec(argv, envp, path, cmdentry.u.index); 1147 /*NOTREACHED*/ 1148 } 1149 goto out; 1150 1151 parent: /* parent process gets here (if we forked) */ 1152 if (mode == FORK_FG) { /* argument to fork */ 1153 INTOFF; 1154 exitstatus = waitforjob(jp, &signaled); 1155 INTON; 1156 if (iflag && loopnest > 0 && signaled) { 1157 evalskip = SKIPBREAK; 1158 skipcount = loopnest; 1159 } 1160 } else if (mode == FORK_NOJOB) { 1161 backcmd->fd = pip[0]; 1162 close(pip[1]); 1163 backcmd->jp = jp; 1164 } 1165 1166 out: 1167 if (lastarg) 1168 setvar("_", lastarg, 0); 1169 if (do_clearcmdentry) 1170 clearcmdentry(); 1171 } 1172 1173 1174 1175 /* 1176 * Search for a command. This is called before we fork so that the 1177 * location of the command will be available in the parent as well as 1178 * the child. The check for "goodname" is an overly conservative 1179 * check that the name will not be subject to expansion. 1180 */ 1181 1182 static void 1183 prehash(union node *n) 1184 { 1185 struct cmdentry entry; 1186 1187 if (n && n->type == NCMD && n->ncmd.args) 1188 if (goodname(n->ncmd.args->narg.text)) 1189 find_command(n->ncmd.args->narg.text, &entry, 0, 1190 pathval()); 1191 } 1192 1193 1194 1195 /* 1196 * Builtin commands. Builtin commands whose functions are closely 1197 * tied to evaluation are implemented here. 1198 */ 1199 1200 /* 1201 * No command given, a bltin command with no arguments, or a bltin command 1202 * with an invalid name. 1203 */ 1204 1205 int 1206 bltincmd(int argc, char **argv) 1207 { 1208 if (argc > 1) { 1209 out2fmt_flush("%s: not found\n", argv[1]); 1210 return 127; 1211 } 1212 /* 1213 * Preserve exitstatus of a previous possible command substitution 1214 * as POSIX mandates 1215 */ 1216 return exitstatus; 1217 } 1218 1219 1220 /* 1221 * Handle break and continue commands. Break, continue, and return are 1222 * all handled by setting the evalskip flag. The evaluation routines 1223 * above all check this flag, and if it is set they start skipping 1224 * commands rather than executing them. The variable skipcount is 1225 * the number of loops to break/continue, or the number of function 1226 * levels to return. (The latter is always 1.) It should probably 1227 * be an error to break out of more loops than exist, but it isn't 1228 * in the standard shell so we don't make it one here. 1229 */ 1230 1231 int 1232 breakcmd(int argc, char **argv) 1233 { 1234 long n; 1235 char *end; 1236 1237 if (argc > 1) { 1238 /* Allow arbitrarily large numbers. */ 1239 n = strtol(argv[1], &end, 10); 1240 if (!is_digit(argv[1][0]) || *end != '\0') 1241 error("Illegal number: %s", argv[1]); 1242 } else 1243 n = 1; 1244 if (n > loopnest) 1245 n = loopnest; 1246 if (n > 0) { 1247 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1248 skipcount = n; 1249 } 1250 return 0; 1251 } 1252 1253 /* 1254 * The `command' command. 1255 */ 1256 int 1257 commandcmd(int argc __unused, char **argv __unused) 1258 { 1259 const char *path; 1260 int ch; 1261 int cmd = -1; 1262 1263 path = bltinlookup("PATH", 1); 1264 1265 while ((ch = nextopt("pvV")) != '\0') { 1266 switch (ch) { 1267 case 'p': 1268 path = _PATH_STDPATH; 1269 break; 1270 case 'v': 1271 cmd = TYPECMD_SMALLV; 1272 break; 1273 case 'V': 1274 cmd = TYPECMD_BIGV; 1275 break; 1276 } 1277 } 1278 1279 if (cmd != -1) { 1280 if (*argptr == NULL || argptr[1] != NULL) 1281 error("wrong number of arguments"); 1282 return typecmd_impl(2, argptr - 1, cmd, path); 1283 } 1284 if (*argptr != NULL) 1285 error("commandcmd bad call"); 1286 1287 /* 1288 * Do nothing successfully if no command was specified; 1289 * ksh also does this. 1290 */ 1291 return 0; 1292 } 1293 1294 1295 /* 1296 * The return command. 1297 */ 1298 1299 int 1300 returncmd(int argc, char **argv) 1301 { 1302 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1303 1304 evalskip = SKIPRETURN; 1305 skipcount = 1; 1306 return ret; 1307 } 1308 1309 1310 int 1311 falsecmd(int argc __unused, char **argv __unused) 1312 { 1313 return 1; 1314 } 1315 1316 1317 int 1318 truecmd(int argc __unused, char **argv __unused) 1319 { 1320 return 0; 1321 } 1322 1323 1324 int 1325 execcmd(int argc, char **argv) 1326 { 1327 int i; 1328 1329 /* 1330 * Because we have historically not supported any options, 1331 * only treat "--" specially. 1332 */ 1333 if (argc > 1 && strcmp(argv[1], "--") == 0) 1334 argc--, argv++; 1335 if (argc > 1) { 1336 iflag = 0; /* exit on error */ 1337 mflag = 0; 1338 optschanged(); 1339 for (i = 0; i < cmdenviron->count; i++) 1340 setvareq(cmdenviron->args[i], VEXPORT|VSTACK); 1341 shellexec(argv + 1, environment(), pathval(), 0); 1342 1343 } 1344 return 0; 1345 } 1346 1347 1348 int 1349 timescmd(int argc __unused, char **argv __unused) 1350 { 1351 struct rusage ru; 1352 long shumins, shsmins, chumins, chsmins; 1353 double shusecs, shssecs, chusecs, chssecs; 1354 1355 if (getrusage(RUSAGE_SELF, &ru) < 0) 1356 return 1; 1357 shumins = ru.ru_utime.tv_sec / 60; 1358 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1359 shsmins = ru.ru_stime.tv_sec / 60; 1360 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1361 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1362 return 1; 1363 chumins = ru.ru_utime.tv_sec / 60; 1364 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1365 chsmins = ru.ru_stime.tv_sec / 60; 1366 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1367 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1368 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1369 return 0; 1370 } 1371